The invention generally relates to computed tomography (CT) systems and, more particularly, to a method and apparatus for predicting failures in x-ray tubes utilized in CT systems.
The sub-systems of a CT system include the x-ray tube, the detector elements and the read-out electronics associated with the detector elements. When any of these sub-systems fail, the CT system formally is taken off-line until the sub-system that has failed has been repaired.
Currently, no suitable techniques have been implemented for predicting when one of these CT sub-systems is going to fail. The x-ray tube is the most often serviced and replaced sub-system of any CT system. Due to the frequency with which replacements must be made, x-ray tubes typically are not covered by the CT systems warranty. Therefore, a separate warranty normally must be purchased for the x-ray tube.
An early prediction of an imminent failure of the x-ray tube could reduce the amount of time the CT system will be down, or inoperable, which would greatly increase customer satisfaction. Also, accurate advance warnings of imminent failures of the x-ray tube could enable hospitals to schedule their down times, thus minimizing the adverse impacts on patient scheduling of replacing the x-ray tube. An early warning of imminent failure of the x-ray tube could also provide servicing personnel with lead-time to order and replace the x-ray tube, which could reduce the costs involved in servicing CT systems.
One approach is to estimate the life span of a CT system x-ray tube based on historical data gathered from other CT system x-ray tubes. For example, the average life span of CT system x-ray tubes has been determined by utilizing historical data relating to when certain x-ray tubes were put into use and when they failed. Since x-ray tubes do not all operate under identical conditions, the average life span is not necessarily a good indicator of when a particular x-ray tube will fail.
Other attempts have been made to predict the life of a CT system x-ray tube, taking into account external operational conditions of the x-ray tube, such as x-ray tube pressure and temperature, to make a prediction. However, this prediction technique has mixed results for predicting the performance of a given x-ray tube.
Accordingly, a need exists for a method and apparatus that enable failures of x-ray tubes of CT systems to be accurately predicted.
The invention provides a method and apparatus for predicting the condition of an x-ray tube of a computed tomography (CT) system. Output values of at least one reference detector element in the CT system are utilized by the apparatus of the present invention in conjunction with a tube condition prediction algorithm to predict the condition of the x-ray tube in the CT system.